The present invention relates generally to the storage and handling of animal wastes generated on-site at facilities at which animals such as hogs or cattle are raised. More particularly, this invention relates to a method and composition for treating on-site animal waste pits or waste holding facilities in order to soften or fluidize hardened solid wastes, e.g. animal excretia, so that the waste materials can be more readily removed from the pits. Removal of collected, hardened solid wastes from such on-site pits has long been a problem. The method and composition of the present invention substantially fluidize hardened, encrusted solids in such waste pits, and thus facilitates their removal. Additionally, preferred methods and compositions of the invention provide for the fixation of nitrogen in the removed waste materials by a nitrogen-fixing bacteria, so that when used as fertilizer, the material removed from the pit is more valuable.
As further background to the invention, ruminant and other similar animals are raised in large numbers for human consumption or for other useful purposes. Needless to say, raising large numbers of such animals leads to the production of large amounts of solid and liquid waste materials. Typically, this waste material is collected and maintained for some period in animal waste holding pits situated beneath a facility in which the animals are housed. Also, sometimes, the wastes are stored and/or processed in lagoons, waste holding tanks or waste wetlands.
Periodically, solid and liquid waste materials must be removed from animal holding pits or the like as they become full. This is usually accomplished by pumping solids and liquids from the pits. The removed materials are then most often spread across crop fields for their fertilizer value. However, a problem encountered in removing the waste materials is that solids in the pits tend to settle to the bottom of the pits and harden. As a result, the breakup and removal of an encrusted layer of solid wastes is quite difficult. Nonetheless, if they are not removed, the solids collect too high in the pits, and dangerous conditions can result. For example, waste pits residing under animal holding facilities can become overly full, bringing the stored wastes into close contact with the animals and potentially exposing them to noxious materials including gases such as ammonia. Thus, difficult as it may be, it is extremely important to successfully remove solids from these waste holding pits.
In response to the problem of encrusted solid wastes in waste pits, there have been developed a number of compositions and methods which may be used to treat the encrusted solids in an attempt to soften them. For example, one method involves the use of complex machinery associated with waste pits which is designed to mix and break up the solids so that they may be pumped from the pit. However, such machinery is expensive, often difficult to maintain and marginally effective in some situations.
Another generally proposed method for treating waste pits to soften solids involves the addition of agents to the pit which are designed to chemically or biologically interact with the materials in the pit. For example, one product commercially available and today (known as "PIT BOSS") includes chelated copper sulfate. However, in practice this product has not been successful in significantly fluidizing or softening solids for their removal. Furthermore, this product includes materials which are harmful to animals and soil quality. Another product known to applicant, Farm Digestant, available from Dawn Chemical Corp. Milwaukee, Wis., is said to contain bacterial enzymes and bacteria which are supposed to interact with materials in waste pits to soften encrusted solids. However, this product is highly unsuccessful in breaking up encrusted solids, potentially because of the type or number of viable bacteria or bacterial enzymes in the product.
Thus, while some methods and compositions have been proposed in the past to treat encrusted solids in waste pits, these simply have not been successful. For example, they lead to no or minimal softening of solids, leaving removal of the solids still difficult. Additionally, other known methods are expensive, when one considers what little actual affect they have on ease of solids removal. Still further, other known methods require the use of expensive equipment, which also exposes farmers to risk and expense of equipment break down and repair costs.
In light of the above, there remains a need and demand for methods and compositions for treating animal waste pits so as to fluidize or soften solids that are hardened in the waste pits. Such a method and composition should have sufficient efficacy to make their use worthwhile from an economic standpoint. Additionally, such a method and composition should be environmentally safe. Furthermore, such a method and composition should not require the use of expensive mixing or other equipment, and should be readily employable by farmers using existing equipment on site. Preferably also, such a method and composition would be effective not only in quickly alleviating serious solids build-up problems, but also provide for safe, long term maintenance of waste pits and other similar holding facilities. The applicant's invention addresses these needs.